Pulp tank structures for pulp molding machines and method



July l0, 1962 `M. P. CHAPLIN 3,043,742

PULP TANK STRUCTURES FOR PULP MOLDING MACHINES AND METHOD Original FiledSept. 29, 1953 2 Sheets-Sheet x 3 ATTORNEY July 10, 1962 M. P. cHAPLlN3,043,742

PULP TANK STRUCTURES FOR PULP MOLDING MACHINES AND METHOD Original FiledSept. 29, 1955 2 Sheets-Sheet 2 INVENTOR MER/.EP Cf/HPL/A/ ATTORNEYUnited States Patent 3,043,742 PULP TANK STRUCTURES FR PULP MOLDINGMACHENES AND METHOD Merle P. Chaplin, South Portland, Maine, assignor,by mesne assignments, to Diamond National Corporation, New York, N.Y., acorporation of Delaware Original application Sept. 29, 1953, Ser. No.382,985, now Patent No. 2,938,582, dated May 31, 1968. Divided and thisapplication .lune 4, 1959, Ser. No. 818,157 6 Claims. (Cl. 162-228) Thisapplication is a division of my copending application, Serial No.382,985, tiled September 29, 1953 and now Patent No. 2,938,582, onMethod of and Apparatus for Making Molded Pulp Articles, the disclosureof said copending application being herein incorporated by reference.

Said parent application discloses integrated apparatus and methods offorming pulp articles and comprises all apparatus and method steps frominitially suction forming an article on a suction die to and includingthe discharge of such article from the apparatus in a condition to bepackaged and ready for the market. That apparatus and method embodies,inter alia, numerous novel features relative to the tank structurecontaining the pulp from which the article is suction formed or molded.That aspect of the parent case forms the subject matter of thisdivisional application and involves both the tank structure and themethod of feeding and handling the pulp in such structure.

The primary object of the invention is to provide for the etlicientsupply of pulp to the forming dies as they are passed through a pool ofpulp in the pulp tank.

A further object of thev invention is to provide means whereby diiferentkinds of pulp may be successively applied to the forming dies as theypass through a single tank, in a simple, convenient and el'licientmanner.

Another object is to provide a surface coating for the article duringthe initial step of its formation.

Another object of the invention is to provide for the formation of anarticle of relatively coarse fibres and also relatively 'tine libres asmay be required for diierent purposes in the finished article.

Another object of the invention is to maintain in the forming tank anequally uniform flow or movement of the liquid generally in the samedirection as the die movement but interspersed with controlled crosscurrentswhich result in an article wherein the pulp iibres extend in alldirections and thus are more efficiently matted than where such pulpbres predominantly are laid in the direction of movement of the 4formingdie through the pulp bath.

In its preferred practical form the tank structure ofthe presentinvention comprises a tank provided therein with a plate curved on theaxis of movement of the forming dies and spaced therefrom. That plate isprovided with openings forming a plurality of nozzles facing in thegeneral direction of rotation of the forming dies, so as to impel themixture against the trailing sides of the dies. Said plate is alsoprovided with a plurality of other openings or orifices to direct thepulp passing therethrough against the leading faces of said dies andsaid nozzles and orifices are spaced from one another to electturbulence conducive to uniform distribution and felting "ire will beapparent from the hereinafter detailed description and appended claimswhen read in conjunction with the accompanying drawings.

The accompanying drawings illustrate one practical embodiment of theinvention, but the construction therein shown is to be understood asillustrative, only, and not as defining the limits of the invention. 4

FIG. 1 is a longitudinal section through a tank structure embodying thepresent invention showing an associated forming drum with dies thereon,said drum being shown partly in section and partly in elevation.

FIG. 2 is a fragmental transverse section on the line 2 2 of FIG. 1.

FIG. 3 is an enlarged fragmental section of a part of FIG. 1, showingthe circulatory action produced by the baffle and orifice plate formingpart of this invention.

FIG. 4 is a fragmental section on the line 4-4 of FIG. 3.

FIGS. 5 and 6y are respectively fragmental plane sections on the lines5-5 and 6'6 of FIG. l.

Referring to the drawings, 8 designates a forming drum or cylinder aboutthe circumference of which is positioned a succession of spaced apartforming dies 9. The drum is mounted to rotate on a horizontal axialshaft 4 and this drum, as well as the dies thereon, may be of anyconventional form common to the art of suction molding drumconstruction; The dies are foraminous or perforated and suction isprovided internally of the drum to cause the accretion of fibres ontothe several dies or.

forms 9 as they pass through and are thus submerged for a time in a poolof pulp or fibre material.

Pulp or libre mixture in a very dilute form, mixed with water or otherliquid, is prepared by various methods and means well known to the art.This dilute mixture in proper relation to libres and liquid isintroduced into a tank 3i. The level of liquid fibre mixture ismaintained reasonably constant at the approximate level indicated at 3a,3a.

As shown in FIG. 1, a pump 3b, driven by any suitable means, such as amotor 3c, through a belt 3d, delivers this liquid-fibrous mixture to apressure chamber 3e through any suitable connecting passage such as 3f.From this pressure chamber 3e the liquid-fibrous mixture is dischargedwith some force into space 3g through directed and controlled openin-gsconstituting nozzles 3h and ori'- tices 3i in a nozzle and orifice.plate 3]'. A 'sufficient quantity of ibre mixture is supplied toestablish a circulation or flow inthe same general direction as themovement of forming dies in their passage through this mixture, shown inFIG. 3 as counter clockwise. The surplus liquid mixture ows over a dam3k at the discharge end of the orifice and nozzle plate, returning to atank 3L, from which it is again recirculated by pump 3b. Additionalliquid-libre mixture is constantly supplied to this tank 3L from anyconvenient and suitable source. Tank 3L may be located below the tank 3,asis here shown, or it may be mounted in any other convenient place orposition so long as it permits the overliow from the formin-g tank 3 toreturn to it by gravity.

The quantity of liquid-bre mixture furnished by the pump 3b andcirculated through the areas 3e and Sgis considerably in excess of thatrequired for the formation of articles on suction dies 9 passing throughthis area, so that adequate circulation and mixing thereof ismaintained, as well as av definite liow of this liquid mixture atgenerally the same speed and in the same direction that the forming diesmove throu-gh it. This direction of ow is partly due to the quantity ofmaterial being furnished by the pum-p 3b, partly to the fact that thedies are moving through the mixture in the tank in the same direction asthis iiow, and partly to the direction of iiow being urged oraccelerated by the shape of the nozzles 3h which direct the flow in thedirection of the die movement. However, in order that the fiow throughthe nozzles Shibe not too directional, or have a tendency to straightenthe fibres out in a unidirectional manner, orifices 3i directintersecting streams at approximately right angles to the streamsdirected through nozzles 3h.

The general direction of stream through nozzles 3h may be `controlled byproper shaping of the deflecting member overlying each nozzle and thesize of the nozzle opening. Similarly the size of orifices 3iV may bemodified so that any suitable or adequate dispersion of fibre mixturemay be obtained. Thearrows in FIGS. 3 and 4 very clearly show theintermingling of the streams flowing through the nozzles 3h and theorifices 3i. One or more orifices 3i are located to intersect the streamfrom each nozzle -to break it up in the marmer generally shown by saidarrows', so that the pulp fibre mixture is distributed evenly over -allsections of each forming die 9 on which the fibres are deposited to formthe article. Any desired number of these nozzles and orifices may beprovided.

It is sometimes desirable to have a relatively thin surface coating onone surface of the article for purposes of appearance, strength,utility7 or to facilitate or aid in some subsequent operation on theproduct itself. To enable articles of this kind to be made by theapparatu-s of this invention, a removable baffle plate 3m may be fixedin the forming tank 3 in the position shown in FIGS. l and 5. Thisbaffle plate serves to deflect a portion .of the fibre mixture suppliedthrough pipe 3f, in the direction Vof die movement, leaving yarelatively quiescent pool 3n of mixture above it. For the fibre mixturesupplied through pipe 3f to reach this pool, it would have to flow,which it will not, in a direction contra to die movement, back past theend of this bafiie plate 3m, and also contrary to the general directionof ow of the mixture through 3g. It is thus possible to supply adifferent fibre -mixture to the pool `area 311 by means of -a pipe Sqand from this pool an initial deposit of fibres may be deposited on thedies 9 as they pass through this area. The quantity of mixture supplied`through pipe 3g is just sufficient to maintain this pool 3u at the samelevel 3a as that of the pulp level in that end of the main tank 3, andto counteract any tendency for the mixture in this tank to fiow in thereverse direction into the pool 3u. Baflies of different lengths may beused so that lthe size of pool 3u may be increased or decreased as maybe desired to produce varying kinds and thicknesses in initial libredeposits on the forming dies. Continued travel of the dies through thespace 3g of the tank 3 superimposes additional fibrous material over thematerial initially accreted on the die surface by continued suction, as`already described.

When some brous materials are utilized, particularly those of waste orother woods of the lower and less expensive grades, it is sometimesimpractical to defibre them `as much as is possible where new wood pulpsare employed, without losing too much of their strength and'serviceability. When such materials are molded by suction, there may bea deficiency of the small size fibrous materials in the liquid fibremixture, thereby leaving a somewhat more open and porous articlestructure than and lstill utilize waste wood and other inexpensivefibrous materials, it'is possible, iaccording to this invention, to

` supply materials which will properly and effectively close thesevoids, Yparticularly on the exposed surface or surfaces of the articleswhile they Iare retained on the vforming die on which they areoriginally accreted. This l may accomplish by inserting a bafiie plate3p (FIGS. l .and 6) at the discharge end of the tank 3, sufficientlyspaced above the nozzle and orifice plate 3j-so that the regularoveriiow of liquid fibrous materials can readily pass beneath this4baiiie plate 3p, overiiow the end of the plate at 3k, and return .tothe tank 3L, to be reciroulated by pump 3b. Due to the rotation of theforming drum 3 and for other reasons, the liquidlevel 3a' at this end ofthe .tank will be the same or slightly higher than the level 3a at theother end of the tank. 'Ihus the stock fed through openings in thebaille 3j will not enter the zones above the baiiies 3m and 3p.

This bafiie plate 3p is removable, but when in use, fits tightly to theend, and both sides of the tank 3, as shown in FIGS. l and 6, to form,in effect, a smalllocalized area therein. Fibrous materials, generallyof a fine texture, and of a kind which will interlock with the othermaterials already accreted on the forming die, are supplied through pipe31' in sufiicient quantity to provide a filler for the voids which mayexist in the accreted article `at this point and effect an adequatefilling and surfacing of the entire exposed area of the article as theforming die leaves the fibre mixture in the machine tank. By sodepositing such materials through a continuous suction method at theextreme end of the accreting cycle, it is possible to surface-seal themolded article, fill voids therein and prevent undue quantities of airfrom being drawn through it, thereby enabling the suction to act withmore effect to solidify the freshly formed structure, eliminate airvoids therein, `and this without requiring the use lof any extraneousmeans.

After an article has been suction formed on one of the dies 9, asstated, continued rotation of the drum carries the article out of andbeyond the tank 3. Since suction is continued through the die, an evensolidification is obtained `over the entire article surface `due toatmospheric air pressure `against the exposed surface thereof.

The article thus formed may be subjected to further operations ormanipulations while on the forming drum and, as the drum rotates, saidarticle is removed from the drum for use or further. treatment as may bedesired and as more particularly described in the parent application.

The foregoing detailed description sets forth the in` vention in itspreferred practical forms but the invention is to be understood as fullycommensurate with the :appended claims.

Having thus fully described the invention, what I claim as new anddesire to secure by Letters Patent is:

l. Method of molding liber pulp articles which comprises: causing asuction forming die cylinder to rotate in partially submerged positionin `a substantially `arcuate pool of pulp, feeding pulp into said poolunder pressure through spaced apart pulp inlets at the bottom thereof ina controlled direction substantially corresponding to the direction ofrotation of the `die cylinder, and simultaneously feeding additionalpulp into the same pool through other interspaced pulp inlets also atthe bottom thereof and directing the feed of such added pulp in adifferent controlled direction than that at which the pulp is fed Vfromthe first mentioned inlets.

2. The method of molding fiber pulp articles in `a pulp moldingapparatus wherein a rotary former having dies is positioned Within atank having' a substantially arcuate plate spaced below the rotaryformer to provide between the plate and the former a pool of pulpmixture, said method comprising: feeding pulp into the bottom of thepool through a plurality of spaced yapart nozzles in the plate in thedirection of the trailing faces of the dies of the former, andsimultaneously feeding additional pulp into the bottom of the poolthrough `a plurality of interspaced feed orifices in the plate in thedirection of the leading faces of the dies.

3. In a pulp molding apparatus wherein a rotary former having formingdies is positioned within la tank containing a liquid-pulp mixture witha substantially a1'-l I plate being provided therein with a plurality ofnozzles facing in the general direction of rotation of the former tofeed the mixture into the pool against the trailing faces of the dies,said plate `also having a plurality o-f orices to feed additional pulpmixture into the pool in a direction of the leading faces of said dies,said nozzles and orifices being interspaced with one another in thedirection of travel of the dies. y

4. Apparatus according to claim 3, wherein the streamsl passing throughthe nozzles and orices are directed at substantially right angles to oneanother.

5. In a pulp molding apparatus wherein a rotary former having for-mingdies is positioned within a tank containing a liquid-pulp mixture with asubstantially arcuate plate within the tank below the rotary former toprovide between the plate and the former a pool of pulp mixture, theimprovement which comprises: a bafe mounted at the inlet end of the tankand projecting an appreciable distance in the direction of rotation ofthe former into the pulp pool between the plate and the former, meansfor feeding one kind of fiber-pulp mixture into the pool above saidbafe, and means for feeding another type of fiber pulp mixture into thetank below the plate, said plate being provided therein with a pluralityof nozzles facing in the general direction of rotation of the former todirect feed of pulp from below the plate into the pool above the platein the general direction of rotation of the former, and said plate alsohaving a plurality of interspaced orices to direct a further portion ofsuch mixture from below the plate through said orifices vinto the poolin an `angular direction intersecting the direction of feed of the pulpmixture through the nozzles.

6. Apparatus according to claim 5, wherein the opposite end of the tankis provided with an overow above the plate for maintaining asubstantially constant pulp bre mixture level in the pool and is alsoprovided at the same end of the tank with a bafe extending into the tankabove the overflow with means -for introducing a predetermined kind ofpulp into the tank above the latter baille.

References Cited in the le of this patent UNITED STATES PATENTS1,360,684 Roberts Nov. 30, 1920 1,707,429 AChaplin Apr. 2, 19291,838,904 Chaplin Dec. 29, 1931 1,884,583 `Crawford Oct. 25, 19321,907,046 Darrah May 2, 1933 2,528,189 Temperley Oct. 31, 1950 2,951,784Moore Sept. 6, 1957

1. METHOD OF MOLDING FIBER PULP ARTICLES WHICH COMPRISES: CAUSING ASUCTION FORMING DIE CYLINDER TO ROTATE IN PATIALLY SUBMERGED POSITION INA SUBSTANTIALLY ARCUATE POOL OF PULP, FEEDING PULP INTO SAID POOL UNDERPRESSURE THROUGH SPACED APART PULP INLETS AT HTE BOTTOM THEREOF IN ACONTROLLED DIRECTION SUBSTANTIALLY CORRESPONDING TO THE DIRECTION OFROTATION OF THE DIE CYLINDER, AND SIMULTANEOUSLY FEEDING ADDITIONAL PULPINTO THE SAME POOL THROUGH OTHER INTERSPACED PULP INLETS ALSO AT THEBOTTOME THEREOF AND DIRECTING THE FEED OF SUCH ADDED PULP IN A DIFFERENTCONTROLLED DIRECTION THAN THAT AT WHICH THE PULP IS FED FROM THE FIRSTMENTIONED INLETS.